Why do good floppy disks go bad?

[Paul Koning]

> On Apr 6, 2016, at 5:18 PM, Chuck Guzis <cclist at sydex.com> wrote:
> 
> Well, I don't know about the consensus, but in my experience, most
> floppies go bad from wear and/or breakdown in the binder.  

I have no experience with this issue in floppies.  But I have a distressingly large quantity of audio cassettes that have gone bad over 10 or 20 years.  It wasn't wear; they weren't played regularly.  Instead, something bad happened with the structure of the coating so that they would squeak loudly when played, both over the playback and physically (noisy passage over the head).  The problem is clearly incompetent chemical engineering, because it showed up only in one brand, which as a result is now on my "never again" list for any of its products. 

	paul